Science 9 Notes 1.7_ Ecological Succession.pdf

Unit 1 Ecology Science 9 Mr. Yeo 2023-2024 Biology STATEMENT OF INQUIRY FOR UNIT 1 ▸ Human interactions with natural systems can have global consequences. KEY CONCEPT: Systems RELATED CONCEPTS: Interactions, Consequences GLOBAL CONTEXT: Globalization and Sustainability Though it may not appear this...

Unit 1 Ecology Science 9 Mr. Yeo 2023-2024 Biology STATEMENT OF INQUIRY FOR UNIT 1 ▸ Human interactions with natural systems can have global consequences. KEY CONCEPT: Systems RELATED CONCEPTS: Interactions, Consequences GLOBAL CONTEXT: Globalization and Sustainability Though it may not appear this way, ecosystems are constantly changing. SuccessionA regular progression of species of replacement over time -- ecosystems evolving Succession is typically slow, but natural disasters or human disturbances can make sudden changes. Definition – Ecological Succession Natural, gradual changes in the types of species that live in an area; can be primary or secondary It is the gradual replacement of one plant community by another through natural processes over time Primary Succession On land, succession that occurs where no soil previously existed is called primary succession. The first species to populate the area are called pioneer species. Examples) Receding glacier (as glaciers melt, bare rock underneath is exposed) and volcanic eruptions (new islands or built or land is covered with lava rock). Lichen is a common pioneer species made up of alga and fungus. Lichen can grow on rock and release acids that help break down the rock into soil. When lichens die, they leave behind organic material that plants can use to grow. Primary Succession Begins in a place without any soil – Bare rock – Sides of volcanoes – Post landslides – Flooded areas Starts with the arrival of living things such as lichens (fungus) that do not need soil to survive Called PIONEER SPECIES Primary Succession: Sand Dune to Forest Primary Succession Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil Primary Succession Simple plants like mosses and ferns can grow in the new soil. Primary Succession The simple plants die, adding more organic material The soil layer thickens, and grasses, wildflowers, and other plants begin to take over Primary Succession These plants die, adding more nutrients to the soil Shrubs and small trees can now survive Primary Succession Insects, small birds, and mammals begin to move in What was once bare rock now supports a variety of life Secondary succession- Succession that occurs in areas where soil exists, but has been damaged or disturbed. -a change to an existing community that does not affect the soil Example- life after a forest fire Secondary Succession Begins in an area where soil is already present, (i.e. a clear-cut forest or following a forest fire). Re-growth after forest fire Secondary Succession How long do ponds last? The Stages of Pond Succession Pond Marsh Dry land/grasses Shrubs Forest 1) As a pond develops, birds and land animals come to inhabit the pond. These are the pond pioneers. 2) As more creatures arrive the debris on the bottom increases. Water plants appears and soon grow all along the bottom. Emergent plants (plants that are rooted and stand above the water surface) grow around the water’s edge. 3) Over time as pond plants grow, die and decompose, layers of debris build up. These layers of decaying matter raise the pond floor over the years. 4) After some time, the pond floor is close enough to the bottom that emergent plants grow all the way across the floor, creating a marsh. The marsh continues to fill in with dirt and debris. Eventually trees grow in the water. It is now a swamp. 5) Over time, the swamp can dry out and the land becomes a forest or grassland. The Stages of Pond Succession Terminology Pioneer species—first species to begin a succession. Climax community —the final stage in a succession. Pioneer Species Climax Community Primary vs. Secondary No soil Beginning à Pioneer species End à Climax community Pioneer Species Soil already exists Seeds have suitable soil conditions. Occurs much faster End à Climax community Climax Community 1. Does this model exemplify primary or secondary succession? Explain. 2. How does the ecosystem change from 1 to 2? What could have caused this change? 3. How does the ecosystem change from 2 to 7? 4. How does the emergence of moss impact the physical environment? 5. How does the emergence of each new population affect the existing population(s) of organisms? 6. How could you improve the model to better show ecological succession in the ecosystem? 7. How does the change in the relative population size of moss compare to the other plants? Why does this occur? True or False?